A method in which a tire inside information acquiring device formed from a sensor module and a wireless communication device is attached inside a tire-wheel assembly, for example, on a rim portion of a rim wheel has been widely used in order to monitor tire inside information such as an inner pressure of the air filled in the tire-wheel assembly obtained by mounting the tire in the rim wheel, and the temperature of the inside of the tire-wheel assembly.
Moisture penetrating into such a tire inside information acquiring device may cause failure in electronic components constituting the tire inside information acquiring device.
In this respect, a method has been known in which: the tire inside information acquiring device is housed in a resin case; and the penetration of moisture into the resin case is prevented (for example, Patent Document 1). Such a tire inside information acquiring device is capable of reducing the incidence of failure in electronic components, because the penetration of moisture into the tire inside information acquiring device is prevented.